A "famous mathematician" is someone who is well-known and respected for their knowledge and accomplishments in the field of mathematics. Full definition
I miss doing it because I met a lot of famous mathematicians through it.» (scientificamerican.com)
The guy who solves this will immediately become the most famous mathematician of the century. (newscientist.com)
He even dismissed the most famous mathematician on the list, the mathematician, philosopher, and bon vivant Bertrand Russell (1500 mD), author of Principia Mathematica. (science.sciencemag.org)